1. Field of the Invention
The present invention relates to an easy-to-manufacture and easy-to-assemble ratcheting-type wrench.
2. Description of the Related Art
Several factors are considered in designing wrenches and spanners, including improving the torque-bearing capacity, providing as many teeth as possible for the drive member, and providing an easy-to-manufacture structure. FIG. 20 of the drawings illustrates a conventional wrench of the type having a handle Bxe2x80x2 and a head in which a drive member Axe2x80x2 is rotatably received. A pawl Dxe2x80x2 is slidably received in a transverse through-hole Cxe2x80x2 in a web between the handle Bxe2x80x2 and the head. However, an end of the pawl Dxe2x80x2 extends beyond the transverse through-hole Cxe2x80x2 and thus adversely affects operation of the wrench when used in a limited space. A two-pawl type wrench was proposcd to solve this problem. As illustrated in FIGS. 21 through 23, the two-pawl type wrench includes a handle 1xe2x80x2 and a head 11xe2x80x2 extended from the handle 1xe2x80x2. A drive member 2xe2x80x2 is rotatably received in the head 11xe2x80x2, a receptacle 12xe2x80x2 is defined in a web between the handle 1xe2x80x2 and the head 11xe2x80x2, and a spring-biased switch member 4xe2x80x2 is mounted in a cavity 13xe2x80x2 in the web. Two spaced pawls 3xe2x80x2 are received in the receptacle 12xe2x80x2 and are biased by two springs 6xe2x80x2, respectively. A threaded end cap 5xe2x80x2 is engaged with a threaded outer end 121xe2x80x2 of the receptacle 12xe2x80x2 to enclose the pawls 3xe2x80x2 and springs 6xe2x80x2. As illustrated in FIGS. 22 and 23, the switch member 4xe2x80x2 is turned to bias one of the pawls 3xe2x80x2 to engage teeth 31xe2x80x2 thereof with the drive member 2xe2x80x2 to thereby change the ratcheting direction of the wrench. However, it was found that the switch member 4xe2x80x2 cannot be reliably retained in place and thus tends to disengage from the cavity 13xe2x80x2. In addition, the pawl 3xe2x80x2 engaged with the drive member 2xe2x80x2 is not engaged with an inner longitudinal wall that defines the transverse through-hole and that faces the drive member 2xe2x80x2. As a result, the torque-bearing capacity of the wrench is poor. Furthermore, the outer pawl 3xe2x80x2 (FIGS. 22 and 23) tends to get stuck when the threaded end cap 5xe2x80x2 is mounted too close to the switch member 4xe2x80x2. On the other hand, if the threaded end cap 5xe2x80x2 is too far away from the switch member 4xe2x80x2, the pawl 3xe2x80x2 cannot be firmly engaged with the drive member 2xe2x80x2. Further, the threaded end cap 5xe2x80x2 tends to be disengaged from the web between the handle 1xe2x80x2 and the head 11xe2x80x2, as the former is in threading engagement with the threaded outer end 121xe2x80x2 of the receptacle 12xe2x80x2.
FIGS. 24 through 26 illustrate another conventional wrench having a substantially V-shape transverse through-hole 25xe2x80x2 in a web between a handle 20xe2x80x2 and a head 21xe2x80x2 thereof. The head 21xe2x80x2 includes a compartment in which a drive member 22xe2x80x2 is rotatably received. A spring-biased pawl 23xe2x80x2 is received in each limb of the V-shape transverse through-hole 25xe2x80x2. A switch member 30xe2x80x2 includes a stem 35xe2x80x2 pivotally received in a cavity 24xe2x80x2 in the web and a thumb-piece 32xe2x80x2 extending from the stem 35xe2x80x2 for manual operation, thereby switching the switch member 30xe2x80x2 between two positions corresponding to two opposite ratcheting directions of the wrench. The thumb piece 32xe2x80x2 of the switch member 30xe2x80x2 includes a downwardly facing receptacle 36xe2x80x2 (FIG. 26) for receiving a spring 37xe2x80x2 and a ball 38xe2x80x2 that is biased by the spring 37xe2x80x2 to be positioned in one of two positioning recesses 281xe2x80x2 (FIG. 25) in a sector-like recessed area 28xe2x80x2 (FIG. 24) of the web. The switch member 30xe2x80x2 may be retained in place reliably. However, a C-clip 33xe2x80x2 is required for mounting the switch member 30xe2x80x2 in place. In addition, processing of the sector-like recessed area 28xe2x80x2 in the web and the V-shape transverse through-hole 25xe2x80x2 is difficult. Mounting of the switch member 30xe2x80x2 as well as the pawl 23xe2x80x2 and associated springs 26xe2x80x2 and threaded end caps 27xe2x80x2 are troublesome and time-consuming. The sector-like recessed area 28xe2x80x2 in the web results in an increase in the overall thickness of the wrench, which limits application of the wrench in limited spaces.
U.S. Pat. No. 6,282,991 discloses a biasing arrangement for a pawl of a reversible ratchet-type wrench. However, the pawl protrudes beyond the handle during change in the ratcheting direction and thus adversely affects operation of the wrench in a limited space, as the protruded portion of the pawl tends to impinge on an object in the limited space.
It is an object of the present invention to provide an easy-to-manufacture and easy-to-assemble ratcheting-type wrench.
In accordance with a first aspect of the invention, a wrench comprises:
a handle comprising a first lateral side and a second lateral side opposite to the first lateral side;
a head extended from the handle, a web being defined between the handle and the head, the head including a compartment, the web including a transverse through-hole having an intermediate portion communicated with the compartment, the transverse through-hole extending from the first lateral side to the second lateral side of the handle, a cavity being defined in the web and communicated with the transverse through-hole;
a drive member rotatably mounted in the compartment of the head and including a plurality of teeth on an outer periphery thereof;
a switch member mounted in the cavity and rotatable relative to the handle between two positions corresponding to two opposite ratcheting directions of the handle; and
a pawl mounted in the transverse through-hole and slidable along a lengthwise direction of the transverse through-hole, the pawl including a side facing the compartment, the side of the pawl including a first toothed portion and a second toothed portion that are selectively engaged with the teeth of the drive member according to one of the positions of the switch member relative to the handle.
In accordance with a second aspect of the invention, a wrench comprises:
a handle;
a head extended from the handle, a web being defined between the handle and the head, the head including a first compartment, the web including a second compartment communicated with the first compartment, a cavity being defined in the web and communicated with the second compartment;
a drive member rotatably mounted in the first compartment of the head and including a plurality of teeth on an outer periphery thereof;
a switch member mounted in the cavity and rotatable relative to the handle between two positions corresponding to two opposite ratcheting directions of the handle; and
a pawl slidably mounted in the second compartment, the pawl including a first side facing the first compartment and a second side facing away from the first compartment, the first side of the pawl including a first toothed portion and a second toothed portion that are selectively engaged with the teeth of the drive member according to one of the positions of the switch member relative to the handle, the second side of the pawl including a notch, the switch member having a portion extending into the notch of the pawl, thereby preventing disengagement of the switch member from the cavity.
The wrench in accordance with the present invention has a simple structure and is easy to assemble by using a C-clip without the need of any screws. In addition, the compartment, the transverse hole and the cavity can be processed by means of milling. No computer lathe is required. Thus, the cost is low, the manufacture process is short, and the production time is also short. Furthermore, the pawl will not protrude beyond the transverse through-hole. Inadvertent switching of the ratcheting direction is avoided. Further, the drive member is firmly engaged with and in intimate contact with the associated toothed portion of the pawl during ratcheting. The risk of slippage or so-called xe2x80x9cteeth jumpxe2x80x9d is avoided. The second side of the pawl contacts with the inner longitudinal wall of the transverse through-hole by a larger area such that the wrench in accordance with the present invention may bear a higher torque. This also prevents inadvertent relative displacement between the biasing member and the pawl. The biasing member in the form of a coil spring provides smooth switching of the switch member, while the rigid pin provides an alternative option for the user. Further, a bridge is provided between the compartment and the cavity, which increases the strength of the wrench, thereby providing a higher torque-bearing capacity. Further, in accordance with the second aspect of the invention, the lower portion of the column extends into the notch of the pawl. Disengagement of the switch member from the cavity is prevented without using any additional elements.
Other objects, advantages, and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.